Apparatus for accretion of fibrous articles on a mold from a slurry of fibers



Feb. 28, 1967 c. H. MAYNE 3,305,315

APPARATUS FOR ACCRETION 0F FIBROUS ARTICLES ON A MOLD FROM A SLURRY OF FIBERS Filed July 14, 1964 INVENTOR: CHARLES HENRY MAYNE j Whyw rl'll FIG! ATT'YS United States Patent F APPARATUS FOR AccRETIoN OF FIBROUS ARTECLES ON A MOLD FROM A SLURRY OF FIBERS Charles H. Mayne, Swindon, Wilts, England, assignor to Hawley Products Company, St. Charles, Ill., 21 corporation of Delaware Filed July 14, 1964, Ser- No. 382,531 5 Claims. (Cl. 162393) This invention relates to the moulding of shaped fibre articles from slurry to produce fibre articles having a curved wall of a thickness that is less than the other dimensions of the article. The term slurry is used in this specification to mean a suspension of fibres in water or other liquid, and the term curved wall is intended to be broad enough to include a wall which is composed of flat surface portions the planes of which form angles with each other.

It is an object of the invention to provide a new or improved method of and apparatus for producing the articles.

In producing from slurry fibre articles having a curved wall it is the general practice to provide a form of suitable screen which constitutes the top portion, or part of the top portion, which during the moulding is submerged in a slurry bath and the interior of which is connected to a suction pump. The pump draws the slurry liquid through the form, leaving the fibre content of the slurry deposited as fibrous pump on the surface of the form. When sufficient pulp has been deposited, the form is raised above the surface of the slurry bath, whereafter the suction is switched off and the article removed from the form. It will be appreciated that if the top surface of the form is convex, a quantity of slurry is raised with the form at the end of the felting operation with the result that the deposition of pulp continues near the lowest center part of the form when the remainder of the form is already out of contact with the slurry, and this results in inequalities in the wall thickness obtained in the different portions of the moulded body. In the case of a form having a convex top surface deposition continues at the lower marginal portions of the form when the center portion has already risen clear of the slurry. In either case the result is the production of a felt body in which the wall thickness varies considerably from one point to another.

It is a more specific object of the present invention to provide an improved moulding method and apparatus for carrying out such method which reduces the tendency to form walls of nonuniform thickness.

The present invention consists in a method of moulding shaped fibre articles from a slurry of liquid containing fibres in suspension comprising the steps of immersing the lower open end of an otherwise air-tight bell enclosing a liquid pervious form in a bath of said slurry, said form being located within said bell wholly above the bottom edge thereof and said bell defining a chamber around the form communicating with the reverse side thereof, subjecting said chamber to suction to cause immersion of the form within the bell and the passage of liquid through the form into the chamber to thus effect deposition of felted fibres onto the surface of the form to produce a moulded body, and subsequently raising the bell to bring the bottom edge thereof above the surface of the slurry whereby the resulting admission of air into the bell will instantaneously terminate deposition of fibres on any part of the form and the continued application of suction to said chamber ensures the absence of a head of liquid at the reverse side of the form.

The invention further consists in an apparatus for moulding shaped fibre articles in accordance with the method referred to in the preceding paragraph.

Preferred embodiments of the invention are herein- 3,306,815 Patented Feb. 28, 1967 after described with reference to the accompanying drawings in which:

FIGURE 1 is a some-what diagrammatic sectional elevation of one form of apparatus according to the invention; and

FIGURE 2 is an axial section of a bell according to the invention equipped with a male form which can be substituted for the bell and female form illustrated in FIG. 1.

Referring now first to FIG. 1, the moulding plant comprises essentially a bath container 1 for a bath of slurry 2, the surface of which is indicated at 3. The container is mounted in a metal framework 4 which at the top is equipped with a cross or bridge member 5. This bridge member carries a ram or jack cylinder 6, the piston rod of which carries a pipe member 17a on which a mould assembly 7 is suspended by a flange connection 8. The mould assembly comprises a bell or cup-shaped member 9 which has at its lower open end an inwardly projecting flange portion 12, and a cup-shaped liquid-pervious form 10 of suitable screen material, extended at its open lower end by a nonporous cylindrical portion 11, is arranged inside the bell with the open end of its extension attached to the inner edge of the flange portion 12. The bell member 9 has, adjacent to the flange 12, an outwardly extending widened portion 13 connected by a flangelike shoulder 14 with the remainder of the side wall of the bell 9. A pair of vertically extending suction pipes 15 penetrate through the flangelike shoulders 14 into the widened portion 13 of the bell member and are connected to a transverse pipe 16 which, through the flange connection 8, communicates with pipe member 17a which telescopically engages a suction line 17 which, through a reservoir 18 and a changeover valve device 19 is connected to a suction pump system 20. The telescopic connection 17, 17a, serves to permit the mould assembly 7 to be moved up and down by the ram device 6. When the mould assembly is lowered so that the lower edge of the bell is immersed in the slurry below surface 3 and the valve 19 is then set to apply suction to the line 17, the slurry will rise inside the cup-shaped form 10 and the pulp liquid will penetrate through the form into the draining chamber formed between the form 10 and the bell 9, flowing down along the form to collect in the widened reservoir portion 13, which acts as a sump from which the collected liquid is withdrawn through pipes 15, 16, 17. The pulp fibres are held back by the form in a well-known manner to build up the moulded layer of felted pulp, and when this layer has reached the desired thickness, the mould assembly 7 is raised by the ram 6 clear of the slurry surface 3. Air then enters the interior of the cup-shaped form, so that the atmospheric pressure forces the slurry instantaneously back into the container 1, thus terminating the felting operation simultaneously all over the surface of the form. Suction is then cut off from line 7, with the result that the air-and-liquid mixture from pipes 15 will flow back into the sump portion 13 of the mould assembly.

The capacity of this sump portion, below the lower edge of the form proper 9, acts as a buffer reservoir and is preferably made sufficiently large to insure that the resulting liquid level in the sump remains below any perforated portion of the form.

If desired, a second ram 21 may, as illustrated, be arranged below the bottom of the tank land carry a mandrel 22 which is slightly tapered and of smaller dimensions than the inner surface of the fibre body to be produced, and which is covered by an inflatable capshaped membrane 23 of rubber or other suitably pliable material. An inflating tube 24 permits air or other suitable fluid to be admitted between the inflatable membrane 23 and the mandrel 22. If desired the mandrel 22 may be introduced into the mould assembly 7 at the end of the felting operation and before the mould assembly is lifted clear of the slurry surface. The membrane 23 can then be inflated to achieve its squeezing action upon the fibre body obtained, and finally the mould 7 and dummy body 22 may be jointly raised by the ram 21 to lift the mould assembly clear of the slurry surface, thus causing the felt body to be pre-squeezed before the membrane 23 is deflated and the ram 21 caused to withdraw the mandrel 22 and membrane 23 from the pre-squeezed felt body.

Since the moulded felt body is, at the end of the moulding operation, arranged in a suspended tool, it can be readily deposited from this tool direct onto a suitable press tool with which it can then be conveyed to a press for afinal squeezing or pressing operation. When the moulding operation was performed in the hitherto usual manner, with the moulded article appearing at the upper side of a submerged form, a separate transfer tool was necessary for picking up the article from the form and subsequently placing it onto a suitable press tool. This transfer tool becomes unnecessary when the moulding is performed according to the present invention.

The modified form shown in FIG. 2 is constituted by a cup-shaped perforated body 25 which has its opening at the top and is suspended by means of a flange-shaped portion 26, which if desired may itself be perforated to form part of the form, at the upper edge of a cylindrical wall 27 which, by a lower flange 28, is connected with an outer cylinder wall 29 the upper edge of which is attached to a top plate 30. The parts 27 to 30 thus form a hollow-walled bell which surrounds the form 25, and the lower edge of which is wholly below the lowermost point of the form. A dummy block 31 fills the greater part of the space inside the form 25 leaving only a narrow jacket 32 constituting the draining chamber, in which liquid which has passed through the form 25 can rise to the level of the upper flange 26. Two vertical suction pipes 33, 33, attached to the flange connection 8 by a cross pipe 34, penetrate through the top wall 30 into the buffer reservoir formed between the inner and outer cylindrical walls 27 and 29 to a point below the lowest point of the form 25 and closely above the bottom flange 28. When the mould assembly illustrated in FIG. 2 is lowered into the tank 1 of FIG. 1 until its lower flange 28 is wholly below the surface 3 of the slurry and suction is applied to connection 8, the slurry will rise in the bell to fill the space between the form 25 and the inner cylindrical wall 27 of the bell, and the slurry liquid will penetrate through the perforations of the form 25, de-

positing a felted layer of pulp on the outer side of the form. The liquid in the draining chamber 32 will then rise above the level of the flange 26 and then flow over into and collect in the annular reservoir formed between the walls 27 and 29 to form a sump above the lower flange 28, from which it is withdrawn through the suction pipes 33. When at the end of the felting operation the mould assembly is raised clear of the slurry, the entry of air into the bell formed by members 27 to 30 -will instantaneously remove all slurry from the surface of the form, while the continued application of suction and the consequent entry of air through the felt and form perforations will cause most of the liquid in the draining chamber 32 to rise over the flange 26 and collect in the reservoir or sump between walls 27, 28 and 29, in which the level will be kept low due to the deep penetration of the suction pipes 33. When finally suction is turned off, any liquid remaining in suction pipes 33 will be readily accommodated in the buffer reservoir enclosed by the said three walls and thus be prevented from reaching again the draining chamber and the interior of the moulded body.

It will be appreciated that when the mould of FIG. 2 is used, by the use of a suitable annular mandrel in place of the mandrel 22 of FIG. 1, a similar squeezing effect to that described with reference to FIG. 1 can be obtained in the case of a body formed at the outer surface of the male form screen,

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. Apparatus for moulding shaped fibre articles from a slurry of liquid containing fibres in suspension comprising a mould assembly including a liquid pervious form mounted within a bell which has an impervious top, impervious side walls and is open at the bottom, said form being disposed within said bell wholly above the bottom edge thereof and said bell defining a chamber around the form communicating with the reverse side thereof, means supporting the mould assembly above a bath of slurry and providing for movement thereof between an upper position where the bottom end of the bell is above the surface of the slurry and a lower position where said bottom end of the bell is immersed in the slurry, and pipe means formed as a part of said supporting means connected to a source of suction communicating with said chamber adjacent the bottom thereof.

2. Apparatus as claimed in claim 1 wherein said supporting means comprises a flanged pipe mounted on a piston rod and telescopically connected to a suction line, a transverse pipe above the mould assembly connected intermediate its ends to the flanged pipe, and wherein said pipe means comprises a pair of vertically disposed pipes connected to the ends of the transverse pipe and extending downwardly therefrom to communicate with said chamber.

3. Apparatus as claimed in claim 2 wherein said bell has an inwardly projecting flange portion at its lower open end and said form is an inverted cup-shaped female member of perforate material extended at its open lower end by an imperf-orate cylindrical portion, said form being arranged inside the hell with the open end of its extension attached to the inner edge of said flange portion of the bell and said bell having an outwardly extending widened portion adjacent its lower end defining with the imperforate extension of the form a sump to said chamber, and said pair of vertical pipes being arranged to pass through the wall of the bell at the widened portion thereof to terminate within said sump.

4. Apparatus as claimed in claim 2 wherein said bell has inner and outer spaced cylindrical side walls surrounding and defining said chamber about the form, said side walls being connected at their lower ends by a flange at the bottom open end of the bell below the lowermost point of the form to provide a sump to said chamber and said outer side wall being connected at its upper end to a top plate forming the closed end to the bell, and wherein said form is a cup-shaped male member of perforate material located within the inner side wall of the bell with its open end uppermost and provided with a flange connected to the upper end of said inner side wall, said pair of vertical pipes being arranged to pass through said top plate and between said inner and outer side walls of the bell to terminate Within said sump.

5. Apparatus as claimed in claim 4 wherein a block is located within the form to restrict the area on the reverse side thereof which may be occupied by liquid to insure rapid drainage of the form when the mould assembly is raised from the bath of slurry to said upper position.

References Cited by the Examiner UNITED STATES PATENTS 240,091 4/1881 Chase 162401 X 677,330 6/1901 Valentine 162393 725,966 4/1903 Howard 162393 DONALL H. SYLVESTER, Primary Examiner.

S. LEON BASHORE, Examiner. 

1. APPARATUS FOR MOULDING SHAPED FIBRE ARTICLES FROM A SLURRY OF LIQUID CONTAINING FIBRES IN SUSPENSION COMPRISING A MOULD ASSEMBLY INCLUDING A LIQUID PERVIOUS FORM MOUNTED WITHIN A BELL WHICH HAS AN IMPERVIOUS TOP, IMPERVIOUS SIDE WALLS AND IS OPEN AT THE BOTTOM, SAID FORM BEING DESPOSED WITHIN SAID BELL WHOLLY ABOVE THE BOTTOM EDGE THEREOF AND SAID BELL DEFINING A CHAMBER AROUND THE FORM COMMUNICATING WITH THE REVERSE SIDE THEREOF, MEANS SUPPORTING THE MOULD ASSEMBLY ABOVE A BATH OF SLURRY AND PROVIDING FOR MOVEMENT THEREOF BETWEEN AN UPPER POSITION WHERE THE BOTTOM END OF THE BELL IS ABOVE THE SURFACE OF THE SLURRY AND A LOWER POSITION WHERE SAID BOTTOM END OF THE BELL IS IMMERSED IN THE SLURRY, AND PIPE MEANS FORMED AS A PART OF SAID SUPPORTING MEANS CONNECTED TO A SOURCE OF SUCTION COMMUNICATING WITH SAID CHAMBER ADJACENT THE BOTTOM THEREOF. 